Re: "The tools version 14.0 is unrecognized. Available tools versions are 2.0, 3.5, 4.0"

I'm guessing the project was created using VS 2015? It sounds like it's expecting to be built using MSBuild 14.0, but SharpDevelop currently only recognises MSBuild versions up to 12.0, which caused me a problem when trying to open Xamarin.Forms projects, where the Windows projects expect MSBuild 14.0. I wrote a bit about it here, you could try the workarounds I found (either add a pre-build command to the project, calling the batch file which sets environment variables to point to MSBuild 14.0, or download the SharpDevelop source code and add a bit so that it recognises when MSBuild 14 is installed).